What to know

• Men with either low or high testosterone face elevated atrial fibrillation risk, following a U-shaped pattern with lowest risk in the middle of the normal range.
• Both low and high testosterone disturb heart cells through separate biological mechanisms, requiring different clinical approaches.
• For testosterone replacement therapy, clinicians should target 350–550 ng/dL rather than high-end levels, using steady-release formulations with structured monitoring.
• While evidence is conflicting across studies, future prospective trials are needed to confirm the therapeutic range and personalized treatment strategies.

“For men who need testosterone replacement therapy, the authors state the goal for clinicians should be aiming to restore testosterone to the middle of the normal range (approximately 350–550 ng/dL total testosterone) rather than pushing it to the high end, using steady-release formulations and structured monitoring.”

Review authors, Study team · News-Medical / Endocrine Society · Aug 31

Rajat S. Barua Co-author, Kansas City Veterans Affairs Medical CenterJournal of the Endocrine Society Publishing venueEndocrine Society Professional organization